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<ul id="index">
  <li><a href="#NAME">NAME</a></li>
  <li><a href="#SYNOPSIS">SYNOPSIS</a></li>
  <li><a href="#DESCRIPTION">DESCRIPTION</a></li>
  <li><a href="#NOTES">NOTES</a></li>
  <li><a href="#RETURN-VALUES">RETURN VALUES</a></li>
  <li><a href="#EXAMPLES">EXAMPLES</a></li>
  <li><a href="#BUGS">BUGS</a></li>
  <li><a href="#COPYRIGHT">COPYRIGHT</a></li>
</ul>

<h1 id="NAME">NAME</h1>

<p>BIO_f_base64 - base64 BIO filter</p>

<h1 id="SYNOPSIS">SYNOPSIS</h1>

<pre><code> <span class="comment">#include &lt;openssl/bio.h&gt;</span>
 <span class="comment">#include &lt;openssl/evp.h&gt;</span>
 
 <span class="variable">const</span> <span class="variable">BIO_METHOD</span> <span class="variable">*BIO_f_base64</span><span class="operator">(</span><span class="variable">void</span><span class="operator">);</span>
</code></pre>

<h1 id="DESCRIPTION">DESCRIPTION</h1>

<p>BIO_f_base64() returns the base64 BIO method. This is a filter BIO that base64 encodes any data written through it and decodes any data read through it.</p>

<p>Base64 BIOs do not support BIO_gets() or BIO_puts().</p>

<p>BIO_flush() on a base64 BIO that is being written through is used to signal that no more data is to be encoded: this is used to flush the final block through the BIO.</p>

<p>The flag BIO_FLAGS_BASE64_NO_NL can be set with BIO_set_flags() to encode the data all on one line or expect the data to be all on one line.</p>

<h1 id="NOTES">NOTES</h1>

<p>Because of the format of base64 encoding the end of the encoded block cannot always be reliably determined.</p>

<h1 id="RETURN-VALUES">RETURN VALUES</h1>

<p>BIO_f_base64() returns the base64 BIO method.</p>

<h1 id="EXAMPLES">EXAMPLES</h1>

<p>Base64 encode the string &quot;Hello World\n&quot; and write the result to standard output:</p>

<pre><code> <span class="variable">BIO</span> <span class="variable">*bio</span><span class="operator">,</span> <span class="variable">*b64</span><span class="operator">;</span>
 <span class="variable">char</span> <span class="variable">message</span><span class="operator">[]</span> <span class="operator">=</span> <span class="string">"Hello World \n"</span><span class="operator">;</span>
 
 <span class="variable">b64</span> <span class="operator">=</span> <span class="variable">BIO_new</span><span class="operator">(</span><span class="variable">BIO_f_base64</span><span class="operator">());</span>
 <span class="variable">bio</span> <span class="operator">=</span> <span class="variable">BIO_new_fp</span><span class="operator">(</span><span class="variable">stdout</span><span class="operator">,</span> <span class="variable">BIO_NOCLOSE</span><span class="operator">);</span>
 <span class="variable">BIO_push</span><span class="operator">(</span><span class="variable">b64</span><span class="operator">,</span> <span class="variable">bio</span><span class="operator">);</span>
 <span class="variable">BIO_write</span><span class="operator">(</span><span class="variable">b64</span><span class="operator">,</span> <span class="variable">message</span><span class="operator">,</span> <span class="variable">strlen</span><span class="operator">(</span><span class="variable">message</span><span class="operator">));</span>
 <span class="variable">BIO_flush</span><span class="operator">(</span><span class="variable">b64</span><span class="operator">);</span>
 
 <span class="variable">BIO_free_all</span><span class="operator">(</span><span class="variable">b64</span><span class="operator">);</span>
</code></pre>

<p>Read Base64 encoded data from standard input and write the decoded data to standard output:</p>

<pre><code> <span class="variable">BIO</span> <span class="variable">*bio</span><span class="operator">,</span> <span class="variable">*b64</span><span class="operator">,</span> <span class="variable">*bio_out</span><span class="operator">;</span>
 <span class="variable">char</span> <span class="variable">inbuf</span><span class="operator">[</span><span class="number">512</span><span class="operator">]</span><span class="operator">;</span>
 <span class="keyword">int</span> <span class="variable">inlen</span><span class="operator">;</span>
 
 <span class="variable">b64</span> <span class="operator">=</span> <span class="variable">BIO_new</span><span class="operator">(</span><span class="variable">BIO_f_base64</span><span class="operator">());</span>
 <span class="variable">bio</span> <span class="operator">=</span> <span class="variable">BIO_new_fp</span><span class="operator">(</span><span class="variable">stdin</span><span class="operator">,</span> <span class="variable">BIO_NOCLOSE</span><span class="operator">);</span>
 <span class="variable">bio_out</span> <span class="operator">=</span> <span class="variable">BIO_new_fp</span><span class="operator">(</span><span class="variable">stdout</span><span class="operator">,</span> <span class="variable">BIO_NOCLOSE</span><span class="operator">);</span>
 <span class="variable">BIO_push</span><span class="operator">(</span><span class="variable">b64</span><span class="operator">,</span> <span class="variable">bio</span><span class="operator">);</span>
 <span class="keyword">while</span> <span class="operator">((</span><span class="variable">inlen</span> <span class="operator">=</span> <span class="variable">BIO_read</span><span class="operator">(</span><span class="variable">b64</span><span class="operator">,</span> <span class="variable">inbuf</span><span class="operator">,</span> <span class="number">512</span><span class="operator">))</span> <span class="operator">&gt;</span> <span class="number">0</span><span class="operator">)</span>
     <span class="variable">BIO_write</span><span class="operator">(</span><span class="variable">bio_out</span><span class="operator">,</span> <span class="variable">inbuf</span><span class="operator">,</span> <span class="variable">inlen</span><span class="operator">);</span>
 
 <span class="variable">BIO_flush</span><span class="operator">(</span><span class="variable">bio_out</span><span class="operator">);</span>
 <span class="variable">BIO_free_all</span><span class="operator">(</span><span class="variable">b64</span><span class="operator">);</span>
</code></pre>

<h1 id="BUGS">BUGS</h1>

<p>The ambiguity of EOF in base64 encoded data can cause additional data following the base64 encoded block to be misinterpreted.</p>

<p>There should be some way of specifying a test that the BIO can perform to reliably determine EOF (for example a MIME boundary).</p>

<h1 id="COPYRIGHT">COPYRIGHT</h1>

<p>Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.</p>

<p>Licensed under the OpenSSL license (the &quot;License&quot;). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>


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